1. Field of the Invention
The invention relates to microstructure elements and to a process for the production of microstructure elements from a metal, plastic or sintered material.
2. Discussion of the Background
Microstructure elements have dimensions in the micron range; they are required, in particular, in precision engineering, micromechanics, microoptics and microelectronics, for example as sensor elements, actuator elements or components in fluid or electronic systems. They are generally employed where properties such as low bulk, low weight and inexpensive manufacture are required. The invention has the object of providing microstructure elements of this type in an economic manner.
It is known that microstructure elements can be produced from plastic, metal or ceramic by the LIGA process by lithography, electroforming and casting. See Kernforschungs-zentrum Karlsruhe, Report 3995 (1985). Plastic microstructure elements are obtained inexpensively and in large numbers by multiple casting from a metallic mold insert by reaction injection molding or injection molding.
The primary structure is obtained by imagewise irradiation of a radiation-sensitive plastic with X-rays or synchrotron radiation, followed by dissolution of the irradiated (or unirradiated) areas of the plastic. The mold insert is produced by electrodeposition of metal in the pre-dissolved areas of the primary structure. The structure of the mold insert is complementary to the primary structure. In spite of all the advantages offered by the LIGA process, such as, for example, substantial geometric freedom in a plane and the wide variety of materials that can be employed, simpler processes are desired in many cases.
It is furthermore known that crystalline materials can be structured by anisotropic etching (Proceedings of the IEEE, Vol. 70 (1982), No. 5, and IEEE Trans. Electron. Devices (ED-25 (1978), No. 10, 1178-1185)). The resultant microstructure elements can only rarely be used directly, since the etched material does not satisfy certain requirementsxe2x80x94for example adequate breaking strength.
One object of the invention, therefore, is to produce microstructure elements from a metal, plastic or sintered material by casting from a mold insert less expensively and more rapidly and to extend the range of structural shapes which can be achieved at acceptable expense.
This object is achieved according to the invention by
(a) producing a microstructured mold insert (primary structure) having at least one cavity open on one surface thereof from a solid body by precision mechanical machining, additive structuring or subtractive structuring;
(b) filling and covering the primary structure with a flowable material;
(c) solidifying the flowable material; and
(d) separating the solidified flowable material from the microstructured mold insert, giving the metal, plastic or sintered material microstructure element, whose structure is complementary to the primary structure.